I've currently released my first virtual drum machine called "Vintage Drum Elements". It's a free VST/AU instrument plugin (32 bit & 64 bit) based on samples from the Yamaha RX5 drum machine. The plugin has all the basic sounds + a couple of cartridge "instrument" sounds sampled from an FM synthesizer. Overall, you have 9 "kits" to play with:

You can download the plugin on my bandcamp account, and it's free: https://singlecycleaudio.bandcamp.com/album/vintage-drum-elements-au-vst-plugin (https://singlecycleaudio.bandcamp.com/album/vintage-drum-elements-au-vst-plugin)

Let me know what you think of it, if you find bugs and if there is things you like to see in a new version. I'm open to suggestions. :)